Cleft Palate represents one of the highest frequencies of congenital malformations found in the human. Teratogens or mutant genes which delay palate shelf movement could be responsible for the congenital defect. The principal objective of the proposed research is to gain an understanding of the processes by which teratogens affect morphogenetic pathways. This objective will be pursued by (1) morphological, pharmacological and biochemical analyses to elucidate the mechanism of palate shelf rotation, and (2) the determination of the mechanism by which glucocorticoids interfere with palate shelf development and cause cleft palate. Among the specific objectives are: (1) To analyze morphologically the skeletal muscle and putative non-muscle contractile systems during development. (2) To determine whether neurotransmitters control palate shelf rotation employing embryo cultures. (3) To determine the synthesis and distribution of the active neurotransmitters in the palate during development. (4) To observe neural components on the cell surface of mesenchymal cells in the palate. (5) To test whether the putative non-muscle contractile systems function(s) in palate rotation employing the glycerinated head preparation. (6) To grow palate mesenchymal cells in culture and to identify specific cell types. (7) To determine whether neurotransmitter regulation of palate shelf rotation correlates with changes in shapes of palatal cells. (8) To investigate aspects of the biochemical control of palate morphogenesis. (9) To determine whether glucocorticoids affect the putative contractile apparatus and might therefore cause cleft palate.